Flavoured beverages are often produced from a beverage emulsion, which is then diluted. Beverage emulsions are generally oil-in-water emulsions which contain oil-soluble ingredients that impart flavour, colour, or other qualities to the emulsion. A diluted, ready-to-drink, beverage typically contains a small amount of beverage emulsion dispersed in water, along with a number of other ingredients, such as sweeteners, acidity regulators and preservatives.
Essential oils are amongst the most widely used flavouring agents in the beverage industry, with citrus oils being particularly popular. Beverages flavoured with citrus oils can be made to have a cloudy or clear appearance.
Cloudiness is largely due to the presence of water insoluble compounds, including but not limited to terpenes, in essential oils such as citrus oils. This appearance may be favoured, for example to give the impression that the drink is rich in juices. However, there is also a large demand for e.g. clear citrus flavoured drinks, which appeal more to consumers.
Traditionally, clear citrus flavoured drinks have been made by removing the terpenes from citrus oils by “washing” the oil with a solvent (also known as deterpenation). A widely-used solvent for deterpenation is ethyl alcohol (J. Owusu-Yaw et. al, Journal of Food Science vol. 51, no. 5, 1986). The technique involves adding a mixture of ethyl alcohol and water to the citrus oil to extract the water soluble components and leave behind the water insoluble terpenes. The water soluble components may then be used to make a clear citrus flavoured beverage. An important drawback of this process is that it delivers a product which is not Halal. Propylene glycol is an alternative, Halal, solvent (U.S. Pat. No. 6,458,408 B1).
Washing citrus oils may, however, have several disadvantages, in particular the high cost of the process. Both ethyl alcohol and propylene glycol are expensive materials. In addition, the process is time consuming, generally requiring a minimum of 48 hours to complete, which in turn may have a negative impact on running costs and yield. Also, batch-to-batch variation is common, making the process unreliable. Washing also may have an effect on the quality of the final product. Some desirable flavour notes of the citrus oil may be lost during this process. Usually, beverages made with terpeneless oils tend to taste “flat”.
Other ways of making clear citrus flavoured beverages have been developed. One technique is to formulate the citrus oils into a microemulsion. However, making microemulsions generally requires high concentrations of surfactants and solvents in order to stabilize the emulsion. Large amounts of such ingredients are undesirable due to regulatory restrictions. Moreover, a large amount of mechanical energy is generally required to make such microemulsions since the ratio of oil to emulsifier is not optimal.
WO2008/039564 A1 discloses a process for solubilizing flavour oils to produce clear beverages.
A key consideration for beverage emulsions is the emulsion stability. It is desirable that the constituent phases of the emulsion remain adequately mixed at least for the shelf-life of the product. Otherwise, the flavour and attractiveness of the beverage may be affected.
There remains an unmet need for a low-cost alternative to washing for producing stable beverage emulsions for citrus flavoured beverages of superior clarity (low turbidity) without the need for undesirable surfactants and solvents.